The United Nations was in the throes of the biggest diplomatic confrontation for decades last night after the US and Britain tabled a new resolution paving the way for an assault on Iraq next month.

The resolution declares that Iraq has failed to grasp "the final opportunity" to avoid war.

But France and Germany, the leading opponents of war, immediately produced a powerful riposte by revealing that they had secured the support of Russia and China for an alternative, peaceful plan that would allow Iraq more time.

This formidable opposition alliance throws into doubt whether the resolution will be adopted, and threatens to wreck the US-British timetable for invasion.

Speaking after dining with Chancellor Gerhard Schröder in Berlin, the French president, Jacques Chirac, said that the majority of the members of the UN security council were in favour of their proposal.

In a response to the US defence secretary Donald Rumsfeld's dismissal of France and Germany as "old Europe", Mr Schröder said the proposals represented the views of "good old Europe".

He said: "An awareness of what war means and what it represents is deeply scored into the collective consciousness of the peoples of Europe. That perhaps allows us to understand better why Germany and France hope for and want a peaceful disarmament of Iraq."

President George Bush said the US and British resolution would test the relevance of the UN, but made it clear that if the UN did not support it the US would go ahead anyway.

"Is it going to be a body that means what it says?" he said. "We certainly hope it does. But one way or the other, Saddam Hussein, for the sake of peace and the security of the American people, will be disarmed."

As he was speaking, the tide of US public opinion was flowing against him. A poll commissioned by the Washington Post and ABC found that a majority of Americans believed that the US should work to gain the support of the security council, even if it meant delaying a war with Iraq. Only 39% said the administration should "move quickly" without security council backing.

The stand-off may mean that the US and Britain will go to war without a UN mandate, imposing an enormous political price on Tony Blair.

The resolution is co-sponsored by the US, Britain and Spain, and backed by Bulgaria. The other 11 members of the security council are, at present, opposed.

In an attempt to win over the waverers, the US and Britain have abandoned hope of a resolution explicitly authorising war and opted for a watered-down version that reiterates much of the last UN resolution on Iraq, 1441.

It accuses Iraq of submitting a weapons statement in December that was false, contained omissions and "failed to take the final opportunity afforded in resolution 1441".

The plan is to put the resolution to a vote soon after the UN chief weapons inspector, Hans Blix, reports on March 7 on any Iraqi progress towards disarmament. War could begin soon afterwards.

The White House spokesman Ari Fleischer said Mr Bush had made it clear that he expected the draft to be considered "in short order". The foreign secretary, Jack Straw, said he expected a vote in a "fortnight or so".

The junior Foreign Office minister, Mike O'Brien, said Britain would examine the French memorandum, but he was sceptical about its contents.

The French foreign minister, Dominique de Villepin, said a second resolution was premature while the arms inspections were making progress.

"There are some countries that think that today it's important to table a second resolution," he said.

"We think for our part it isn't necessary or useful, since we are resolutely in a time of inspections. That is why we have said we could not accept this second resolution."

The German foreign minister, Joschka Fischer, who is due in London today for further discussion, also said the resolution was unnecessary and did not correspond to the consensus reached by EU leaders last week.

Arab officials urged the EU meeting to avoid a war, which they said could deepen frus tration and militancy in the Middle East.

The Arab League's secretary general, Amr Moussa, told reporters: "You can never belittle the consequences of any war, especially in an area like the Middle East, already frustrated with the Israeli occupation and the bias towards Israel. So adding insult to injury is too much for us."